Solidification of liquid fuel



Patented Sept. 1952 UNITED ST'lES middle SOLIDIFICATION 0F LIQUID FUEL assignors to the No Drawing. Application June 14, 1949, Serial No. 99,107

(Granted under the act of March 3, 1883, as

amended April 30, 1928; 370 0. G. 757) 15 Claims.

The invention described herein, if patented, may be manufactured and used by or for the Government for governmental purposes, without the payment to us of any royalty thereon.

This invention relates to the solidification of liquid hydrocarbon fuels.

The solidification of liquid hydrocarbon fuels by emulsifying the same in alginic acid or in a water-soluble salt of alginic acid, followed by congealing in an aqueous solution of a calcium salt has been described in the foreign patent literature, e. g., in British Patent No. 450,206, De Granville, and British Patent No. 481,392, Pouettre. The solidified bodies obtained by the methods set forth in these patents burn with a slow flame without exploding, and are reconverted into liquid hydrocarbon fuel by squeezing, shredding, or similar mechanical operations.

Alginic acid is a product found in nature and has up to now defied synthesis. The natural product is principally extracted from kelp, varies greatly in quality, depending e. g. upon the method of extraction, the species and age of the kelp and the location of its growth. Consequently, the solidified product made by the use of alginic acid or alginate lacks uniformity with regard to gasoline content of the solidified body, syneresis (release of water after congealing), storage stability, etc.

We have found that liquid hydrocarbon fuel can be solidified by emulsifying it in an aqueous solution of a water-soluble synthetic polymer characterized by repeating CH2.CH groups, and congealing the emulsion by converting the dispersant phase into a water-insoluble and substantially hydrocarbon-insoluble complex, e. g. by contact with an aqueous bath of a calcium salt such as calcium chloride.

Thus, it is an object of our invention to solidify a hydrocarbon fuel by means of a synthetic polymer.

Another object of our invention is a solidified hydrocarbon fuel having uniform properties of low flammability, storage life and being mechanically reconvertible into liquid hydrocarbon. V

A further object of our invention is a reliable and inexpensive method of preparing liquid hydrocarbon fuel for stockpiling and transportation for military and civilian purposes.

Other objects and advantages of our invention will appear from the following detailed descrip tion of a preferred example of carrying the same into practice.

We have found that liquid hydrocarbon fuel emulsions suitable for the purpose of our invention may be obtained by dispersing the gasoline in an aqueous solution of a water-soluble poly- 2 meric substance characterized by repeating -CH2.CH groups capable of forming waterinsoluble and gasoline-insoluble calcium complexes by reacting with a calcium salt containing congealing bath. Thus, the continuous phase of the liquid gasoline emulsion is converted into a:

solidified gel serving as a supporting structure wherein the liquid hydrocarbon phase is dispersed as tiny droplets. Among suitable water-soluble polymeric substances are alkali and other monovalent salts of polyacrylic acid, of polymeric crotonic acid or of polymeric vinyl acetic acid, e. g., sodium polyacrylate, potassium polyacrylate, ammonium polyacrylate, sodium polyvinyl aces tate, sodium polycrotonate.

Sodium polyacrylate (e. g., the commercial product now sold by Rohm and Haas under the name of RHotex) is prepared either by polymerizing sodium acrylate, e. g., with hydrogen peroxide or potassium persulfate as low temperature polymerization catalystsyor by converting polymerized acrylic acid into its sodium salt by methods well known to the art. Sodium polyacrylate is water-soluble even in the highly polymerized state. a

The preparation of other polymeric monovalent salts (e. g. alkali metal salts or ammonium salts) of acrylic acid, vinyl acetic acid, crotonic acid and of other starting materials characterized by the CH2:CII- (vinyl) configuration are prepared similarly either by polymerizing the monomeric salt or by converting the polymerized acid into the corresponding salt.

Copolymers of the above polymeric substances with compatible water-soluble monomers are within the contemplation of our invention; thus, the polymeric sodium salt of acrylic acid copolymerized with vinyl methyl ether may be used as the dispersant for the gasoline. The dispersant for the gasoline may also consist of a mixture of the. above-mentioned polymeric substances with each other and/ or with alginic acid or alkali metal alginate.

The following specific example illustrates a method of carrying our invention into practice by the use of sodium polyacrylate as dispersant for gasoline; it will be understood, however, that our method may be carried out by the use of the above-mentioned other synthetic water-soluble polymeric monovalent compounds as well.

Example acrylate until all the gasoline has been dispersed.

The resulting emulsion is then introduced into a 10% aqueous .solution of calcium chloride, wherein it'immediately gels. We prefer to introduce the emulsion into the congealing bath dropwise, so as to obtain pellets of substantially uniform size.

The resulting solidified body, .e.-g. of pellet shape, loses a substantial amounto'f water during the next few hours. It also .gives ofilgasolin'e vapors immediately after congealing and therefore should be aged in a chamber equipped with gasoline vapor recovery means.

dispersed gasoline content is up to about 75%. The solidified body is non-explosive, burns with a slow flame, and yields most of its gasoline content by squeezing; a nearly complete gasoline recovery roan Z be :obtained .by .r-shredding :and

pressing.

.The strength o fal'theaemulsi'fying sodiumptzlyacrylatessolution inlay .ibe .zizaried;- 1 star .instance, within-i thexstren'gth "range :of. the .order. of 1 "to 21%:arid preferably less than'3% :Less'er strengths are'i'feasiblei :b'u't result ainzjthe introduction of an undesiredquantitynof .waterrin the r solidified-gel structure; .conversel'y zanexcessively strong sodium'rp'olya'crylate solution :lovverst the. proportion by :weight on dispersed gasoline and thus may prove less reconomica'l for storage .and itra'nsport. Likewise, 'the relative. proportionsby :volume. of gasoline :and "emulsifyinglibath :may :be varied within suitable limits.

'slnsteadcf a.'l0% 'aqueouszsolutionof calcium chloridezaforxthe congealing bath, :aqueouss'olutionsx'of' different-strengths.andpfodifferent: calcinmrsalts', ergrcalcium mitrate-orcalcium sulfate may:.-bemsed,a'as long .asz'thererare :enough positive calcium; ions ainzithe congealing bath to convert the wateresoluble. dispersant. phase-10f thesgasolineeoontaining emulsion :into. a iwa tereinsoluble and'substantially hydrocarbon insoluble complex. Thus, good results have been obtained. with.ai30i% strength calcium chloride congeal'ing: rbath, and even rgreaters strengths'upito: the: saturation .point may; be. employed (solubility; of; calcium :chloride in-"oold' wa-t'er ;59.5 .:g.5iper -1-00wml.). .jIf .a calcium nitrate-. bath :is employed zlesser strength, say 151% and;lpreferablyinotabove 10%, ought to be'employed, and excessrnitrateshould be removed from the gels because of the flammabilityof. nitrate complexes. Gelsformed-in calcium sulfate congealingbathssare .nota'as Strong as those formed in. calcium chloride baths. Likewise, the corresponding salts :of other alkaline earth metals havingoa higheromolecularweight than calcium (e...g. of strontium-or bari-um) --may:be:used: in the .congealing ,bath instead oracalcium salt.

Variationsfrom-and modificationscf the specific. example-of .our -invention,.-above set forth,

the .,group consisting vof. alkali metal salts and F ammonium .salts .and characterized by repeating -:;C.Hz.CH

groups;-and'reactingt'heliquid.dispersantflphase with'amember'ofthe group'consisting of alkalineearth chlorides, alkaline earth nitrates and alka line earth sulfates, to convert said phase into a Water-insoluble and hydrocarbon insoluble solid alkaline earth complex.

2. The process of making solidified hydrocarbon .geLJcomprising, emulsifying liquid hydrocarbon in .an aqueous solution of a polymeric water-soluble monovalent saltfbeing a member of the group eonsisting .ofalkali-metal salts and ammonium After aging the gasoline content of the body remains sub-' stantially uniform during prolonged storage; its

..saltsa-nd characterized by repeating groups, and reacting the liquid dispersant phase Withan alkaline earth chloride to convert said phase into a water-insoluble and hydrocarboninsoluble soild-alkali-ne earth complex.

3. The-processofmaking solidified hydrocarbon gel, comprising emulsifying liquid hydrocarbon in i an aqueous solution of-a polymeric wateresoluble monovalent saitnbeing a member: of .the group consisting of alkalig-metal-saltsand ammonium salts and characterizedby repeating groups and reacting the liquid dispersant phase with an alkaline earth nitrate ,to..cohvert. .said phaseinto a water insoluble and. hydrocarboninsolu-ble solid alkaline earth complex.

4. i'Iheprocess ofyrnaking. solidified hydrocarbon gkcomprising emulsifying liquid hydrocarbonin an aqueous solution-of, a polymeric water-soluble monovalentalkali. metal .salt characterized by repeating p groups, and reacting; the liquid .dispersant phase with an alkaline earth sulfate to convertflsa'id phaseijinto a waterjeinsoluble and hydrocarboninsoluble solidalka'line earth. complex.

5. Thepmcess of making solidified hydrocarbion gel, comprising emulsifying liquid hydrocarboninan aqueous solution.oflapolymeric.watersoluble monov alent-v sodium salt icharacterizedlby repeating a i '---.'CH2.CH'.

groups, and reacting the liquid."dispersant phase with calcium chloride to conye'rtsaid phaseiinto I a water-insoluble andhydrocarbonginsoluble solid calcium complex.

"6. 'The process of makinga solidified hydrocar n e mpr i g emulsifying.liquidhydrocarbon in an aqueous; solution .of a water-soluble alkali'metalpolyacrylate, and reacting the liquid hon-insoluble solid alkaline earth polyaflflate complex.

'7:"I?he process of. making solidified .hyd'rocarbon ge'lfcornprising emulsif n liquidliydmcarbon in anagueous solution of. sodiumpolyacrylate, and reacting thelli'qu'id dispersantphase-with bon gel, comprising emulsifying liquid hydr0car-.

bonin an aqueous, solution ofsodiumpblyacrylate of a'strength of from about 1'% tofa'botlt2%,.and reacting th'e liqui'd "dispersant phase, with ,a' memb'erof 'the'group consisting of alkaline earth chlorides; alkaline earth nitrates and alkanne earth sulfates, toi convert said phase into a waterinsoluble and hydrocarbon-insoluble solid alkaline earth polyaorylate complex.

9. The process of making solidified hydrocarbon gel, comprising emulsifying liquid hydrocarbon in an aqueous solution of sodium polyacrylate, and reacting the liquid dispersant phase with calcium chloride; to convert said phase into a water-insoluble and hydrocarbon-insoluble solid calcium polyacrylate complex.

10. The process of making solidified hydrocarbon gel, comprising emulsifying liquid hydrocarbon in an aqueous solution of sodium polyacrylate, and reacting the dispersant phase of said emulsion with an aqueous solution of calcium chloride to form a water-insoluble and hydrocarbon-insoluble calcium polyacrylate complex.

11. The process of making solidified hydrocarbon gel, comprising emulsifying liquid hydrocarbon in an aqueous solution of sodium polyacrylate, and reacting the dispersant phase of said emulsion with an aqueous solution of calcium chloride of about 10% strength to form a waterinsoluble and hydrocarbon-insoluble calcium polyacrylate complex.

12. The process of making solidified hydrocarbon gel, comprising emulsifying liquid hydrocar bon in an aqueous solution of sodium polyacrylate of a strength of from about 1% to about 2% and reacting the continuous phase of said emulsion with an aqueous solution of calcium chloride of about 10% strength to form a water-insoluble and hydrocarbon-insoluble calcium polyacrylate complex.

13. A solidified non-explosive hydrocarbon containing gel essentially comprising a dispersion of droplets of gasoline in a solidified water-insoluble and hydrocarbon-insoluble solid alkaline earth polymeric dispersant phase, said dispersant phase being the reaction product of (1) a member of the group consisting of alkaline earth chlorides, alkaline earth nitrates and alkaline earth sulfates with (2) the liquid dispersant phase of a liquid emulsion of said gasoline as the dispersed phase in an aqueous solution of a water-soluble polymeric monovalent salt being a member of the group consisting of alkali metal salts and ammonium saltsand characterized by repeating -CH2.CH

groups as the dispersant phase.

14. A solidified non-explosive hydrocarbon body comprising a dispersion of gasoline in a;

solidified dispersant phase essentially comprising;

the water-insoluble and substantially hydrocarbon-insoluble reaction product of 1) a member of the group consisting of alkaline earth chlo-,

rides, alkaline earth nitrates and alkaline earthf sulfates with (2) the liquid dispersant phase of aliquid emulsion of gasoline as the dispersed phase in an aqueous solution of a water-soluble alkali metal polyacrylate as the dispersant phase.

15. A solidified non-explosive hydrocarbon body comprising a dispersion of gasoline in a solidified dispersant phase essentially comprising the water-insoluble and substantially hydrocarbon-insoluble reaction product of calcium chloride with the liquid dispersant phase of a liquid emulsion of gasoline as the dispersed phase in an aqueous solution of a water-soluble alkali metal polyacrylate as the dispersant phase.

KARL A. FISCHER. OTTO F. HECHT.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

1. THE PROCESS OF MAKING A SOLIDIFED HYDROCARBON GEL, COMPRISING EMULSIFYING LIQUID HYDROCARBON IN AN AQUEOUS SOLUTION OF A WATER-SOLUBLE POLYMERIC MONOVALENT SALT BEING A MEMBER OF THE GROUP CONSISTING OF ALKALI METAL SALTS AND AMMONIUM SALTS AND CHARACTERIZED BY REPEATING
 14. A SOLIDIFIED NON-EXPLOSIVE HYDROCARBON BODY COMPRISING A DISPERSION OF GASOLINE IN A SOLIDIFIED DISPERSANT PHASE ESSENTIALLY COMPRISING THE WATER-INSOLUBLE AND SUBSTANTIALLY HYDROCARBON-INSOLUBLE REACTION PRODUCT OF (1) A MEMBER OF THE GROUP CONSISTING OF ALKALINE EARTH CHLORIDES, ALKALINE EARTH NITRATES AND ALKALINE EARTH SULFATES WITH (2) THE LIQUID DISPERSANT PHASE OF A LIQUID EMULSION OF GASOLINE AS THE DISPERSED PHASE IN AN AQUEOUS SOLUTION OF A WATER-SOLUBLE ALKALI METAL POLYACRYLATE AS THE DISPERSANT PHASE. 